Water-saving technology developer Xeros Technology Group said chairman John Samuel had resigned, with immediate effect, to devote more time to external roles.
Current director David Armfield, who joined the board lat June, had been appointed as interim chairman.
'On behalf of the board, I would like to thank John for his considerable contribution as chairman since the business listed in March 2014,' Armfield said.
'It has progressed from early stage technology development to its current position of having multiple proprietary applications in the process of commercialisation.'
At 9:56am: (LON:XSG) Xeros Technology Group Plc share price was 0p at 16.75p